1. Field of the Invention
The present invention relates to cycloaliphatic polyepoxy compounds and preparation thereof. Such cycloaliphatic polyepoxy compounds are useful typically as energy-ray-curable monomers for use in ultraviolet-curable inks for ink-jet process.
2. Background of the Invention
Ink-jet recording systems have been more and more used, because they are inexpensive, easily produce full-color images, and carry out printing with low noise and high quality. Among them, an ultraviolet-curable ink-jet recording system receives attention, because this system causes less odor and can carry out printing even on recording media that are poor in ink absorption, as compared with solvent-based ink-jet recording systems. Such ultraviolet-curable inks include, for example, radically polymerizable inks and cationically polymerizable inks.
Cationically polymerizable inks do not suffer from polymerization inhibition by the action of oxygen, in contrast to radically polymerizable inks. In addition, they can use light sources with low illuminance and are not so irritative. They, however, produce printed images having quality often varying with temperatures and humidity, and it is difficult to yield high-quality printed images free from feathering or bleeding at high humidity. As a possible solution to these problems, Japanese Unexamined Patent Application Publication (JP-A) No. 2005-29632 discloses an ink composition for ink-jet process which contains a cycloaliphatic polyepoxy compound having a novel structure as an ultraviolet-curable monomer. According to the technique disclosed in the document, the cycloaliphatic polyepoxy compound is synthetically prepared by epoxidation of a corresponding cyclic olefin compound with peracetic acid. However, such cycloaliphatic polyepoxy compounds synthetically prepared using peracetic acid are generally highly viscous, and the resulting inks may not be discharged satisfactorily.